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8310502: Optimization for j.l.Long.fastUUID()

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Reviewed-by: liach, alanb
This commit is contained in:
shaojin.wensj 2023-06-29 13:37:32 +00:00 • committed by Jie Fu
parent 07734f6dde
commit 20f7d05ef2
5 changed files with 96 additions and 43 deletions
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43
src/java.base/share/classes/java/util/UUID.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2023, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -25,10 +25,13 @@
package java.util;
import java.nio.charset.CharacterCodingException;
import java.nio.charset.StandardCharsets;
import java.security.*;
import jdk.internal.access.JavaLangAccess;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ByteArray;
/**
* A class that represents an immutable universally unique identifier (UUID).
@ -463,7 +466,43 @@ public final class UUID implements java.io.Serializable, Comparable<UUID> {
*/
@Override
public String toString() {
return jla.fastUUID(leastSigBits, mostSigBits);
long lsb = leastSigBits;
long msb = mostSigBits;
byte[] buf = new byte[36];
ByteArray.setLong(
buf,
0,
HexDigits.digit((int) (msb >> 56), (int) (msb >> 48), (int) (msb >> 40), (int) (msb >> 32)));
buf[8] = '-';
ByteArray.setInt(
buf,
9,
HexDigits.digit(((int) msb) >> 24, ((int) msb) >> 16));
buf[13] = '-';
ByteArray.setInt(
buf,
14,
HexDigits.digit(((int) msb) >> 8, (int) msb));
buf[18] = '-';
ByteArray.setInt(
buf,
19,
HexDigits.digit((int) (lsb >> 56), (int) (lsb >> 48)));
buf[23] = '-';
ByteArray.setLong(
buf,
24,
HexDigits.digit(((int) (lsb >> 40)), (int) (lsb >> 32), ((int) lsb) >> 24, ((int) lsb) >> 16));
ByteArray.setInt(
buf,
32,
HexDigits.digit(((int) lsb) >> 8, (int) lsb));
try {
return jla.newStringNoRepl(buf, StandardCharsets.ISO_8859_1);
} catch (CharacterCodingException cce) {
throw new AssertionError(cce);
}
}
/**